@fry_p The issue is really NFS v3 (period). NFS v3 is not a secure protocol at all.
The FOS engine uses nfs to capture and deploy images to the target computers.
The /images directory is read only. The /images/dev is read write.
Images currently being captured are written to /images/dev/<mac_address>
Once the capture is done, the FOS engine connects to FOG via FTP and moves the files from /images/dev/<mac_address> to /images/image name. Its a bit of ingenious code that does this since a linux move is just a rename of the directory path so there is no copying about of multi-gigibyte files once the upload is over.
With current NFS v3 the only option you have is that you can restrict who can mount the nfs share to a certain IP range. But anyone in that range can mount the share (using unix) without restriction.
So now you have to ask yourself what are the risks to having this share open to world read/write on /images/dev and world read on /images? Are you storing any PII or GDPR regulated data on those shares? What are your true risks here.
The better answer would be for FOG to support NFSv4 with kerberos authentication. That’s possible but not currently implemented in FOG. That setup also puts a bit more burden on the FOG server OS to have kerberos setup.
I have also thought about NFS via a SSH (TLS) tunnel. But that based on research seems to cause a serious performance impact of image throughput. I also thought about imaging over openvpn, but that would require FOS to support an openvpn client. This openvpn route does open some interesting possibilities, but from a performance standpoint I think NFSv4 is probably the right answer.